A wide variety of machines utilize tracks, commonly as ground engaging propulsion elements, but also for other purposes such as torque transmission and conveying. It is common for such tracks to include a plurality of rotatable track engaging elements, with the track forming an endless chain that is moved about the rotating elements during operation. The demands placed upon such machines and their associated track assemblies can be quite substantial, and machine tracks are often relatively robust to provide a long operating life despite significant mechanical stresses, strain and wear experienced during operation.
One conventional track system known from track-type tractors and the like utilizes one or more rotatable idlers which engage the tracks, typically working in conjunction with a drive sprocket. The idlers passively rotate to guide the associated track about a desired path. It is common in conventional track systems for the rotatable idler to roll against “rails” located on links of the track chains. More recently, designs have been implemented in certain machines where the rotatable idler and track are configured such that the idler contacts the track between adjacent parallel track chain assemblies, rather than riding on the rails.
One such design is known from U.S. Pat. No. 5,829,849 to Lawson. In the Lawson strategy, an idler contacts roller bushings located between track chain assemblies to support and guide the track as it rotates to propel the machine. Tapered side portions of the idler provide lateral guiding of the track chain assemblies. Lawson overcomes certain design and operating issues associated with conventional systems where the idler rides on rails. While Lawson provides a successful strategy, there is always room for improvement, particularly with regard to the wear characteristics of the system.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.